Blow-out preventers are devices placed on a subsea well to prevent a catastrophic blowout. In particular, blow-out preventers are designed as a last-line of defense to prevent leakage of contents of the well into the sea. Two component systems in a BOP to address this problem involve an annular BOP, which is a rubber device to close and completely shut off an empty or drill-in bore, and an actuated ram, which is designed to close an open hole or close around a fixed pipe size. Certain actuated rams may have the capability to shear the pipe, if necessary, for an emergency disconnect. Actuation of both of these devices involves hydraulic systems and moving components. Sealing the well is a preferred solution in a catastrophic blowout, but cutting or shearing of the drillpipe is performed for emergency disconnect situations.
Pipe shearing is an important activity for handling emergency conditions on drilling vessels and platforms. A BOP on the seafloor may include devices to perform pipe shearing when emergency situations arise that require fast action. Pipe shearing is conventionally carried out through mechanical means, such as pipe shearing rams. However, shear rams are limited by the thickness of the pipe they can cut. When an emergency arises and contents of the well are escaping through the drillpipe, immediate action is necessary to preserve human life and to preserve the environment.